It is known that the earth is under a relatively strong electric field, observed between the surface of the earth and its surrounding air. This field arises from the fact that the air has a net excess of positive ions (i.e. is positively charged), whereas the earth's surface has a net excess of electrons (i e. is negatively charged). By the laws of electrostatics, each of these net charges tends to be uniformly distributed everywhere in the air and on the ground surface, respectively.
In spite of these quasi-uniform distributions, the induced electric field is still relatively strong, approximately 130 V/m measured on the surface of the sea. Although this voltage looks attractive for generating electricity, the problem is that it is accompanied by a relatively small electric-current density: the air's net positive-ion density n.sub.i is very low, so that the resulting net ion-current density J=n.sub.i .times.v.sub.i toward the earth's surface is almost zero. Thus, for example, if one connects one bare end of an insulated wire with the earth's surface (negatively charged) and the other bare end with a horizontal metallic surface in the (positively charged) air, one would measure very little current flowing through the wire, proportional to the exposed area of the metallic surface. Accordingly, to date there has been no successful way developed to use the earth's electric field for significant electricity production.
A need therefore exists for a method of generating electricity by taking advantage of the earth's electric field. The present invention addresses that need.